A medium agitating type wet pulverization/dispersion machine is widely used for pulverization processing and dispersion processing in the fields of inks, paints, ceramics, metals, inorganic substances, organic substances, magnetic substances, pigments, pharmaceuticals, and the like. The particle diameters after processing are frequently 1 μm or less, and the materials are frequently in high concentrations or in high viscosity. There are many kinds of medium agitating type wet pulverization/dispersion machines, and Patent Document 1 describes one example thereof and a pulverization/dispersion processing system using the example.
As shown in FIG. 7, the processing system 110 described in Patent Document 1 includes a medium agitating type wet pulverization/dispersion machine 120, a holding tank 140 of a material to be processed, a circulating pump 130, and circulating lines 150 connecting the above components to each other. The material to be processed that has been put in the holding tank 140 is circulated through the circulating lines 150 by the circulating pump 130, and is repeatedly subjected to pulverization/dispersion processing by the medium agitating type wet pulverization/dispersion machine 120. As a result, the pulverization/dispersion processing progresses to the whole material to be processed in the system, and the miniaturization of particles gradually progresses. Accordingly, it is desirable to obtain the information enabling the successive and objectively judgment of the progress of the pulverization/dispersion processing.
The information that is most desirable for the judgment of the progress of the pulverization/dispersion processing is the particle size distribution of the material to be processed. A laser diffractometry is used for the measurement of a particle size distribution in many cases. For example, Patent Document 2 describes a method of measuring powdered coal to be used in a high concentration with a particle size distribution measuring apparatus of a laser diffractometry system. Patent Document 2 describes a particle size distribution measuring apparatus capable of continuously measuring the particle size distribution by attenuating high concentration particles in an air current with a carrier gas.
Moreover, Patent Document 3 describes an example of using a particle size measuring machine of the laser diffractometry system in wet sand pulverizing equipment pulverizing original sand with a wet pulverizer. That is, it is described that the particle size of sand (particle diameter: 5 mm or less) after the pulverization of the original sand is measured, and the supply quantity of the original sand to be supplied to the wet pulverizer is controlled on the basis of the result of the measurement.
However, because the conventional methods use optical methods, samples must be transparent, and it is necessary to dilute the samples to the degree of about 10 mg/L generally. On the other hand, it is unable to dilute the concentration of the material to be processed for measurement in the pulverization/dispersion processing system shown in FIG. 7. Moreover, even if a part of the material to be processed is sampled for measuring the material, it is difficult to measure the sampled part in a short time. Consequently, it is difficult to judge the progress of the pulverization/dispersion processing successively and objectively in a pulverization/dispersion processing system using a medium agitating type wet pulverization/dispersion machine.
Patent Document 1: Japanese Patent Application Laid-Open Publication No 2005-125192
Patent Document 2: Japanese Patent Application Laid-Open Publication No. 2005-241480
Patent Document 3: Japanese Patent Application Laid-Open Publication No. 2000-312837